Quick change electrodes



QUICK CHANGE ELECTRODES Filed Nov. 25, 1938 2 Sheets-Sheet 1 Fi .1. 29 a0 a2 Inventor: Ralph Afiilbert,

W His i'ltorneg.

D 10, 1940- R. A. GILBERT 2,224,598

QUICK CHANGE ELECTRODES Filed Nov. 25, 1938 2 Sheets-Sheet 2 Inventor: Ralph A.6ilbert,

His Attorney.

Patented Dec. 1o, 1940 PATENT OFFICE omcx'cnamcn nuac'rnonas BalphLGilberLPittafleldMaI aIignorto Genetalklcctricoolnpany.acorpotationof New York Application November 25, 1938, Serial No. 242,286

My invention relates to resistance welding apparatus for sequentially performing a plurality of different welding operations.

It is frequently n to perform on one 5 article different welding operations and in the past it has been the general practice to perform like operations on one machine and pass the article from machine to machine until all the different operations had been performed or to m use a different set-up on one machine for the different welding operations each of which is completed on all the articles before. another operation is started.

These procedures require either a large number of welding machines or protracted periods of inactivity for the welding operator while a single machine is being set up for the various welding operations.

It is an object of my invention to provide apparatus suitable for sequentially performing a plurality of welding operations in a single machine.

It is a further object of my invention to provide a welding machine with a plurality of electrodes each of which is adapted to perform a' different welding operation and each of which in its welding position is automatically supplied with an amount of welding current particularly suited to the welding operation for which a each electrode is adapted.

It is another object of my invention to provide a counter electrode having substantially diflerent work engaging surfaces which cooperate with each of the work engaging surfaces of a plurality of electrodes each of which is adapted to performa different welding operation.

It is another object of my invention to provide as part of the welding apparatus a work engaging fixture having index means cooperating with a stop located relative to a welding electrode in its welding position for correctly positioning the work relative to the electrode when asshowninFig. 1; Fig. 6 is a detailviewof the clamp forming part of the fixture of Figs. 4 and 5; and Fig. 7 is a wiring diagram illustrating the connection of the control switches illustrated in Fig. 2 by means of which the proper amount of welding current is supplied to the three different electrodes illustrated in Figs. 1 and 2.

In the resistance welding machine illustrated in the drawings. a plurality of electrodes it, ii and I! are adjustably positioned over a cooperating or counterelectrode II in order to perform m three different. projection welding operations. The electrode I. is adapted for welding angles N to the inside surface of a transformer tank It, and the electrodes ii and I2 are respectively adapted for welding cover lugs i6 and lifting lugs II to the outside surface thereof. The counterelectrode i3 is provided with recesses l8 adapted to hold the angles II and the electrodes Ii and I2 are provided with holding clips I! for position- 20 ing thereon the cover lugs i6 and lifting lugs I1. Each of the electrodes l0, Ii and i2 has a work engaging surface that is adapted to engage a substantially diflerent portion of the work engaging surface of thecounterelectrode i3. As indicated in Fig. 3, the electrode l0 engages the area a, electrode ii engages the area b, and the electrode i2 engages the areas c of the counterelectrode l3.

Electrodes l0, ii and I2 are attached to the lower surface of a sector-shaped plate 20 which is pivotally attached at 2i to a sector-shaped terminal plate 22. Plates 20 and 22 are formed of copper or some similar material of good electrical conductivity and a substantial portion of the upper surface of the plate 20 makes an electrical contact with a substantial area of the lower surface of the plate 22. An arm 23 attached to the plate 20 and extending over the edge portion of the plate 22 is provided with a plurality of rolls 24 which engage a track 25 secured to the outer periphery of the plate 22. This track is made of steel or some other wear resisting material and through the agency of rolls 24 and arm 23 acts as a support for the outer edge portion of the plate 2|. The arm 23 is also provided with a latch 2i having a handle 21 on its exterior surface and a dowel pin (not shown) on its inside surface. This dowel pin is adapted to engage dowel holes 22 inv track 25 when the electrodes III, II and I2 are properly positioned over the counterelectrode ii. The electrodes III, II and- II are moved into desired positions over the counterelectrode I! by rotating the plate 2. relative to the plate 22 through the agency of the other terminal of the secondary of the welding II and asupportlng standard ll.

handle :1 attached to the latch is. This latch is normally biased to a position holding the dowel pin thereon in the dowel holes above referred m Welding current is supplied to the electrodes II, II and i2 through the plates 2. and 22 from one terminal I! of the'secondary of a. welding transformer which is connected to-terminal portion 3| of the plate 22. Welding current is also supplied to the counterelectrode II through a supporting arm 3| which is connected to' the transformer. The arm ll forms a part of the welding machine which is provided with a ram 32 to the lower end of which the plates 2. and 22 and the electrodes II, II and" are attached. The reciprocation of the ram "relative to the arm 31 applies welding pressure to the work in- Jserted between cooperating electrodes. The

tank II is supported during welding on electrode Each electrode II, II and limits welding position is automatically connected to a source of welding, current particularly'suited for the welding operation to be performed thereby. This isaccomplishedthroughtheagencyofcam operated switches, is and II supported on plate 1 22 by bracketsv It and conduits ll within which the control wires for these switches are located. Switches 33, and ii are operated by cam 38 attached to 'thearm 23 .which moves with the sector plate I. inlocating the electrodes II, II and I 2 in' their welding Po tions. As shown in the diagram of-I'ig. 7, switches 33, 34 and 35 when closed selectively energize relays 30, l0 and i which through their associated contacts vary l v the number of primary windings 42 of the weld- 1 ing transformer connected to the source of supply I. By thus varying the number of primary windings, the proper amount of welding current is supplied by the welding transformer 44 through its secondary 45' to coop rating electrodes. It isto be noted that thenumber of primary turnsenergized through the relays 39, ll and is made adjustable-through the agency of adjustable contacts .48.

The control circuit for the relays 39, 4. and

'llalsoincludesacamoperatedswltchllwhich is opened andclosed by cam 48, the arrangement. being such that the control circuit is closed after cooperating electrodes have engaged the work inserted therebetween and is opened before these electrodes are removed from the work through the agency of the reciprocated rain".

The tank II is positioned relative to cooperating electrodes through the agency of a fixture ll attached'thereto. This fixture is provided with aplurality of equally-spaced openings" in which the shankor terminal por-' tionsof'indexingpins llJlandllareclamped by set screws located in the outsideperipheryoftheringl' 'I'hesepinsareofdiflerent predetermined lengths and whenin engagement withstopsltltan'dll positionthet'ank ll relative to operating electrodesso, that the parts ll, il and l'l'arewelded tothetankin' desired locations. For example, when the pin it thestop "the cover lugs II are properly located. When the pins l8 engage the aasascs of the welding machine. They may be attached directly thereto or through the intermediary of a support plate on which they are mounted as illustrated in the drawings.

The ring ll is attached to the tank II by a clamp 5a which cooperates with two flanged clamping dogs II. The clamp and clamping dogs are adiustably positioned in the openings 50 of the ring 49 in positions such that they do not interfere with the indexing pins II, i!

and 63 also supported in these openings of thering. asshowninl'ig.5,theringliisprovided with a recess within which the turned-over edge of the tank I! is located and theclamp and dogs engage the outside of the tank surface on the other side oi. this turned-over edge. The

tank is properly located in the ring by positioning a marked portion of thetank, for example the back seam I thereof, opposite a referencemark 6| onthering. Theproperlocation of the indexing pins II, 52 and I in the ring 49 may be obtained through theuse of a templet 62 such as illustratedinFlg. 4.

As illustrated in Figs. 5 and 6, the clamp-Fl comprises a bolt 83 whose shank is supported in the ring I. The head of the bolt is threaded for the reception oi a feed screw It provided witha handle 65 by means ofwhich a clamping member 66 also supported thereon is forced into engagement withthetank II. The dogs ll have eccentric head portions 61 and by properly locating the dogs I! in-the ring withregard to their eccentric heads", the tank I! may be accurately centered in' the ring when secured thereto thro ugh theagencyof the clogs it and the clamp". I I

In view of the above description the. manner in which the welding apparatus is employed is believed to be obvious. Briefly, it'is as follows:

The tank i5 is located in the ring 0 which is clamped thereto. This ring having the indexing pins II, I2 and I3 properly located therein positions the tank ll relative to cooperating electrodes when these pins engage stops II and II.

with the work thus properly located, the electrode for performing each welding operation is swung into position over its cooperating or counter-electrode thereby actuating one of the switches B, N and I! which'automaticallyconnects the proper amount of welding current thereto.- I g It is apparent that, according to the work and the welding operations to be performed,

various fixtures provided withvarious arrangements of index members may be used in following the teachings of my invention. It isabo apparent that special electrodes may be associatedinmanywayswiththeotherpartsofthe welding machine so that they canbe moved into and out of welding-position. Furthermore. ar-

rang'ementsotherthanthosedlsclosedmaybe employedfortoapairofcooperating electrodes the proper'amount of welding curtendedintheappendedclaimstocoverallmch variations and modifications a'scome within the true spirit and scope of my invention.

' rent for the operation to beperformed thereby.

whatlclaimasnewanddesiretosecureby' Letters Patent of the United States is: I H 1. Resistance welding apparatus plurality of electrodes each of which is adapted to perform a diiferent welding operation, means the movement of any one of said electrodes into its welding position for supplying thereto a predetermined amount of welding current particularly suited for performingthe welding Mb I tion for which it is adapted.

2. Resistance welding apparatus comprising aplurality of electrodes each of which is adapted to perform a diiferent welding operation, means for selectively moving any one of said electrodes into a welding position, sources of welding current suitable for performing the welding operations for which each of said electrodes is adapted, and means responsive to the movement of any one of said electrodes into its welding position for connecting the proper source of welding current thereto.

3. Resistance welding apparatus comprising a plurality of electrodes each of which is adapted to perform a different welding operation, sources of welding current suitable for performing the welding operations for which each of said electrodes is adapted, a movable support for said electrodes, means for moving said support to locate any one of said electrodes in its welding position, and means responsive to the movement of said support and including a cam and a plurality of switches positioned in the path of movement of said cam for connecting the proper source of welding current to each electrode when it is located in its welding position.

4. Resistance welding apparatus comprising a plurality of electrodes each of which is adapted to perform a diiferent welding operation in conjunction with a common counterelectrode, means for selectively positioning each of said plurality of electrodes in a welding position opposite said counterelectrode, and means responsive to the movement of said positioning means for adjusting in accordance with the welding operation to be performed the amount of welding current supplied to each of said plurality of electrodes when it is in its welding position.

5. Resistance welding apparatus comprising an electrode, a fixture having a plurality of index members supported thereon, means for attaching said fixture in a predetermined position on an article to be welded, and means including a stop selectively engaged by said index members for positioning said fixture and said article relative to said electrode. v

6. Resistance welding apparatus comprising an electrode, a fixture having a plurality of index members supported thereon, means for locating said fixture on an article to be welded and for attaching it thereto, and means including a stop selectively engaged by said index members for positioning said fixture and said article relative to said electrode.

7. Resistance welding apparatus comprising an electrode, a fixture, means for clamping said fixture in a predetermined position on an article to be welded, a plurality of index members, means for attaching said index members to said fixture in predetermined positions thereon, and means including a. stop selectively engaged by each of said index members for positioning said fixture and said article relative to said electrode.

8. Resistance welding apparatus comprising an electrode, a fixture, means for clamping said fixture in a predetermined position on an article to be welded, a plurality of index members, means for locating said index members on said fixture in accordance with a plurality of welding operations to be performed on said article.

means for attaching said index members in thedesired locations on said fixture, and means including a stop selectively engaged by each of said index members for positioning said fixture and said article relative to said electrode.

9. Resistance welding apparatus comprising an electrode, a fixture, means for clamping said fixture in a predetermined position on an article to be welded, index means on said fixture, and means including a plurality of stops selectively movable into operative or inoperative positions and selectively engaged by said index means for positioning said fixture and said article relative to said electrode.

10. Resistance welding apparatus comprising an electrode, a fixture, means for clampina said fixture in a predetermined position on an article to be welded, a plurality of index pins of predetermined lengths, means for attaching said pins to said fixture in redetermined positions thereon, and means including a stop selectively engaged by each of said index pins for positioning said fixture and article relative to said electrode.

11. Resistance welding apparatus for securing attachments to a cylindrical shell comprising cooperating electrodes, a ring having a plurality of circumferentially spaced openings therein and having a diameter greater than the diameter of said cylindrical shell, means for centering and clamping said ring to the surface of said cylindrical shell, a plurality of index pins having projecting end portions of predetermined lengths and having terminal supporting portions adapted to be located in the openings in said ring, means for securing the terminal portions of said pins in the openings in said ring in accordance with a predetermined pattern, and means including a stop selectively engaged by the projecting end portions of said pins for positioning said cylindrical shell in a plurality of welding positions relative to said-electrodes.

12. Resistance welding apparatus for securing attachments to a cylindrical shell comprising a fixed electrode, means including said fixed electrode for supporting said cylindrical shell, a ring having a plurality of circumferentially spaced openings therein and having an inside diameter greater than the diameter of said cylindrical shell, means mounted on said ring for centering and clamping it in a predetermined position on said cylindrical shell, a plurality of index pins having projecting portions of predetermined lengths and having terminal supporting portions adapted to be located in the openings in said ring, means for securing the terminal portions of said pins in the openings in said ring in accordance with a predetermined pattern, and a stop selectively engaged by each of said index pins for positioning said cylindrical shell relative to said electrode, said stop being located in a predetermined position relative thereto.

13. Resistance welding apparatus for securing attachments to a cylindrical shell comprising a fixed electrode, means including said fixed electrode for supporting said cylindrical shell, a plurality of electrodes each of which cooperates with said fixed electrode in performing a different welding operation when positioned opposite thereto, sources of welding current suitable for performing the welding operation for which cooperating electrodes are adapted, a shiftable support for positioning each of said plurality of electrodes in its welding position opposite said fixed electrode with its work engaging surface opmeiteadiflerentportionoltheybrkenl l inzsuriweotnidnxedelmmeem :hittingsddsupporttoloeetemone-oi' plurality ofelectrodee in 'iteweldin oppositemidnxedelech'odqeca'mmmntedon mid shittable support, meene'including 'l, pluraiityotmtcheepoeitionedinthepethotmove mentotmdcemtoreunnectingthenmer' source of welding current of etch ofrfld phi: nlity of electrodes moved into cooperating pontion with said fixed electrode, mane 101' movin; said support toward and any from mid flxedelectrodetomovecooperetingelectrodeeto-e mdendamtromonemothegeringhem.

e plurality of circumferentiflly meoed openinea therein Ind having en inside diameter greater magma then the mmof am cylindrical mu;

meme mountedon mid rlnl i'oreent'erin and ,cllmplnz it in predetermined poeitlon on an y d fl d ll lfl'll loi indu pins-hupredeterminedlenlflll f zn iecfl cm flomn end having terminellumrtinlportiom adepted to be located intheomnina in mid meme toraecurin the terminel partied; otnid pins'intheopenin'a'innidrinainaecordmce with a. predetermined pattern, and stop menial aelectivelyengqedbyeechotmdipdexplns. "for pod tioninz said cylindrical eheil relative to 

